Due to growing concern of energy shortage and environmental challenges, solar energy has been regarded as a potential solution. At the heart of the photovoltaic industry is a solar cell which converts photon energy to electrical energy. With rapid technological advancements in the photovoltaic industry, solar cells have been widely used in various applications. From the creation of solar cells, the technicians working in this technical field have devoted themselves to improve conversion efficiency of solar cells.
As shown in FIG. 37, a solar cell unit in the prior art typically comprises a semiconductor plate 10 of p-type doped configuration or n-type doped configuration; a p+ doping region 20 is arranged on a primary surface of the semiconductor plate 10, while an n+ doping region 30 is arranged on another primary surface of the semiconductor plate 10. Wherein the thickness of semiconductor plate 10 is typically less than 200 μm. The aforementioned structure puts constraint on the thickness of the solar cell unit; namely, the solar cell unit in aforementioned structure cannot be made fairly thin. In the case the thickness of a solar cell unit is made fairly thin, in particular the thickness of the solar cell unit is close to or smaller than the width of depletion region, the light adsorption efficiency of the solar cell unit would be weakened, and the electrical current in the solar cell unit would become smaller when the thickness of the solar cell unit becomes thinner, which consequently curtails performance of the solar cell unit. Thus, the utility of the semiconductor plate material cannot be further improved. Particularly, it is impossible to increase the number of semiconductor plates, when the semiconductor plates are made out of a substrate.
Additionally, in aforementioned structure, electrodes have to be built on two surfaces of the semiconductor plate so as to form the positive and negative of the solar cell unit. However, the electrodes would block light and degrade energy conversion efficiency of the solar cell unit.
Accordingly, it is necessary to provide a solar cell unit and a method for manufacturing the same to solve some of the aforementioned problems.